The use of known elements of this type generally requires specialized manpower. Indeed, it is generally necessary to use an on-site crimping machine in order to assemble these elements laterally one to the other and/or the engagement of two successive elements in the longitudinal direction has to be carried out by force which, in certain cases, may pose a problem of alignment and correct positioning.
One of the essential objects of the present invention is to propose a roof cover element which can be mass-produced industrially with precision in a factory at a low cost price compared with known preformed roof cover elements. This implementation does not generally require specific equipment and knowhow. This, in the current circumstances, allows fitting by a single, non-specialist person.
Belgium Patent BE-A-528371 discloses roof cover elements obtained from a rectangular metal sheet. These elements are equipped on their raised edges with a clip and with a stop border allowing the engagement of juxtaposed receiving elements, the folding forming a butt joint. It Is thus unnecessary to resort to the crimping of juxtaposed elements, but the problems caused by force-assembly are not solved.
French Patent FR-A-929893 describes metal roof cover sheets with rolled lateral edges engaging in the corresponding edge of a neighbouring sheet. A stapling device is provided, consisting of a transverse strip welded to the upper part of each sheet and intended to receive a fold of the sheet immediately above. These sheets are rectangular. They have no upright lateral edges forming the said upright joints which guarantee leaktightness in the event of heavy rain.
The roof cover element according to the present invention consists essentially of a panel having substantially the shape of an isosceles trapezium of which the two non-parallel sides have the said rims, the length of one of the bases of the trapezium being substantially equal to that of the other base increased by twice the width of the wall of the said rims, so as to enable the ends of the rims on the side of the shorter base to engage with the ends located on the side of the longer base of another element extending in the extension of the said specific element and parallel to the said rims.
Advantageously, the panel has a retention member on its aforesaid face close to its longer base. The retention member makes it possible to immobilize, with respect to each other and in a specific position, two successive elements engaged in the extension of each other in the longitudinal direction of their rims.
According to a particular embodiment of the invention, the aforesaid retention member has the form of a clip oriented towards the shorter base of the element on which it is provided. This base has an edge which is at least partially folded in the form of a clip towards the face opposite that on which the retention member is arranged. This allows the retention member of a specific element to interact with the aforesaid folded edge of another element engaged in the extension of this specific element in a direction parallel to the longitudinal direction of their rims.
Further details and particular features of the invention will emerge from the description, given hereinbelow by way of non-limiting example, of a particular embodiment of the invention, with reference to the appended drawings.